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Friday, 25 January 2013

Wind Farms and Fire Risk

The anti-wind lobby has adjusted its focus, in recent months. There has been a concerted effort to paint wind farms as:- A probable cause of bushfire- A significant obstacle to fire fighting effortsFor instance, this article in the Herald Sun yesterday (which seems to have been removed from the Herald Sun website), or this (PDF) submission to the Senate Inquiry into 'Recent trends in and preparedness for extreme weather events'For this blog post, I'll focus on the first of the two accusations pointed at wind farms. There is actually some historical data on this issue. The table below is extract from testimony contained in the Macarthur Wind Farm panel report, Page 247 from 2006:

No wind turbine fires. By the end of 2006, the cumulative installed capacity in Victoria was ~100 MW - see here or check out the sheet named [Cm_Cap] in the workbook. But, what about post-2006, and what about areas outside of Victoria? There have been three wind turbine fires since 2006. All three were contained and controlled by fire fighting authorities.

They are breathlessly referenced when attempts are made to suggest wind turbines are a fire hazard. See, for instance, this press release from the 'Australian Wind Turbine Awareness Group' - an organisation that seems to exist only in the header of this particular press release. (Their liberal use of the comic sans font probably gives you an idea of the authenticity of the information within)There's plenty of falsehoods contained in that document, but let's focus on the instancing of turbine fires as evidence that they pose a fire risk. To determine the number of operational hours for each wind turbine across the NEM, all you need is the date the wind farm was registered, and the number of wind turbines at each facility. I grabbed both, and calculated the number of hours logged for each wind turbine up to and including 25/01/2013.Check out the 2006 statistics in this spreadsheet, or the wind farm classification and operational time data in this spreadsheet. If you have any questions on the data, buzz me via Twitter. Of all the wind turbines connected to the NEM (remember, excluding NT and WA), there have been a total of 44,495,998 operational hours - or, 5,079 years.

Assuming a 5 hour duration for each fire, the average percent of time that the NEM's wind turbines were on fire was about 0.00003%. That's three fires, in 5 millenia of wind turbine operation. This is a small number of fires, given the conditions that wind turbines endure in Australia. They incorporate temperature sensors, and they shut down when they reach a pre-programmed value. I've seen waves of heat move across a wind farm, reflected as blue points on a SCADA screen as the turbines shut down in response to the temperature.

From these data, if you were to stand underneath a randomly selected wind turbine, you'd have to wait approximately 1,693 years before it burst into flames. To put it another way: In the past 8 years, wind turbines spent ~15 hours on fire, and ~5,079 years being not on fire. Out of the three wind turbine fires, none resulted in a consequent bushfire.

A wind turbine fire is an innately dramatic occurrence. Due to the sheer salience of the event, we’re unlikely to consider the mathematics of this issue. The more you actively dislike wind turbines, the more you’ll ignore instances that are counter to your beliefs (a wind turbine that is not on fire), and the more you’ll over-value instances that confirm your ideas (a wind turbine that was on fire). More posts coming soon, on this topic.